Differentials
by Senshi'sBard
Summary: Ami manages to solve the cases of Calculus and Tuxedo Kamen in one blow... sort of.


Hello world! This is my first go at this whole fanfiction deal so... erm... yeah.

Disclaimer: None of these peeps are mine. Neither is the idea of eating French fries with hot sauce. I saw a girl do that in school once. I was repulsed.

* * *

"I really don't think this is a good idea," said Ami nervously, hunching into the booth. "Are you sure we actually _want _to speak to him?"

"Of course," Rei replied, her mouth a tight line. "He's not the type to go blabber to the world that he knows who the Sailor Senshi are, but still, it would be better if… if we got things sorted out."

Usagi wailed and slumped forward on the table. "Why _him_, of all people?" Her lip jutted out in an overdone pout. "He's always in the _way!"_

"And what if he doesn't even show up today?" Makoto poked one of her fries into hot sauce and popped it in her mouth. "Eurgh. That's repulsive. No one can consume that much salt at one time."

"We don't all have gourmet appetites," Minako pointed out as Usagi reached over and grabbed a handful of fries.

Rei was not to be distracted. "If he doesn't show up today, then we'll just wait for Usagi to hunt him down."

Her mouth full of half-chewed, deep-fried potato, Usagi screeched, spewing a flurry of mush over the table. The other girls recoiled with yelps. After a heavy swallow, Usagi managed to blurt out, "Why _me?"_

"Because you always run into him." Rei clasped her hands together, all prim poise and matter-of-factness. "Admit it."

"That's not true!" Usagi cried desperately. "Sometimes, he runs into _me!"_

Ami smiled into her Calculus textbook. That was simply not true.

"Oh, come on now, odango, don't give yourself too much credit." All five girls flinched at the sound of a familiar voice. Chiba Mamoru had appeared, presumably leaning over the booth, since his voice seemed to be floating down from right above Ami's head. Eight fearful eyes bored into him, watching every move he made, but Ami fixed her gaze steadily upon her book.

"Everyone knows you're the one who's magnetically drawn to me," Mamoru finished. Usagi hissed a stream of infuriated little squeaks, but he ignored her. "You're studying Calculus, Mizuno? Aren't you in your first year of high school?"

"Oh!" Ami's fingers trembled as she clutched the spine of the book. She could feel his breath on her scalp, and she knew it would be too awkward to turn all the way around in her seat and speak up to him. "Cram school," she whispered to the page. It responded silently with _Differentials_, the same word she'd been reading for the past ten minutes. She tried not to panic, to slow her breathing. Did he have to just stand there and pretend he didn't know? What was he going to _do? _If her mother found out that she was a Sailor Senshi… if _anyone _found out… she couldn't bring herself to finish the thought.

"Ami-chan's a genius," said Minako cheerily. "Sit down, Mamoru?"

"Suppose I'd better," said Mamoru, matching her airy mood. He slipped onto the bench next to Ami, whose quivering hands practically dropped the book. She felt Mamoru eyeing her.

"Don't have a heart attack, now," he said easily, and out of the corner of her eye she saw him produce a friendly grin. "What did you think I was going to do, Mercury-san? Write to the papers?"

_Mercury-san_. Her heart almost did stop, but she found a wave of relief ebbing through her. She glanced up at him cursorily with a small grin.

Seemingly satisfied, he crossed his legs and examined the three girls across from him; Usagi, on Ami's left, was oblivious as she tore through her plate of fries. "You know," Mamoru mused, lowering his voice, "I really should have known. It's all so obvious now." Rei stiffened as he caught her eye. "Miss Spitfire - " He turned to Makoto. "Miss Thunderbolt -"

Mako grinned at Rei, who seemed to be steaming a bit from the scalp. Ami chanced a smile and absently fingered a small tube of ointment in her pocket.

"Matchmaking flirt," he nodded to Minako. She set her elbows on the counter and leaned forward almost suggestively, but Ami supposed it was her act of defiance; _nothing _could keep Mina-chan from flirting, certainly not being called out on it.

He turned to Ami, who once more became very fascinated by that one word, _Differentials_. "Mercury-san," he muttered to himself. "Oh, I've got it. 'Everyone freeze and let me analyze this'."

Minako and Makoto laughed, but Ami's brow furrowed. '_Everyone freeze'… ?_

"And odango," Mamoru said. "The easiest one, I think." He took a napkin from the middle of the table and scrunched it up in his fist… Ami stared. A fist with a very long, tender scratch, slightly green, passing between the knuckles. Such a familiar shade of green…

"Throw things haphazardly in the air, and magically they hit their target every time," Mamoru said with a smirk, chucking the balled-up napkin at Usagi's head, which it bounced off lightly. Makoto and Rei cascaded into laughter, while Minako grinned on good-naturedly.

Usagi's face turned an uncomfortable shade of purple. "_Baka!" _she screeched. "Maybe my aim is so impeccably fine-tuned that… that it searches out evil and destroys it!" She stuck her nose in the air. "My shoe _knew _you were no good!"

Mamoru snorted. "'Impeccably', eh? Pretty advanced vocabulary for an odango atama."

"_Stop calling me that!" _Usagi roared.

Ami's heart had sped up once more. If he had only run into them after the battle with the youma, before they'd de-transformed, then how in the world did he know…?

"Mamoru-san," she said quietly, looking up at him once more. "You didn't see us fight the youma, did you?"

He shook his head innocently. "I just turned the corner and saw you change back."

"So you didn't see Tuxedo Kamen?" Ami pressed on.

Minako giggled. "Why so curious, Ami-chan? Usagi's the one who's obsessed with Cape Boy."

"_Did you_?" Ami demanded, her gaze locking with Mamoru's.

"No," he said, bewildered. "I didn't know he was there."

She nodded silently and turned back to her book.

"I'm not obsessed with him!" said Usagi, blushing furiously.

"Oh, give it up," said Minako. "Now that Mamoru-san knows, anyway…" She turned to Mamoru, excitement dancing in her eyes. "Since you know that Usagi is Sailor Moon," she hissed in a rather loud stage whisper, "then… I mean… well, she and Tuxedo Kamen are kind of a _thing_, if you know what I mean." She gave Mamoru a big wink. "But don't tell anyone that, either, because we're not sure who he is yet."

Mamoru's face remained quite unchanged - a stone face, thought Ami, perfectly smooth, perfectly emotionless. A mask, even. No, they didn't know who Tuxedo Kamen was - for _certain_.

"I wouldn't tell anyone," Mamoru said lightly. "And curse you all like that? The Dark Kingdom would be on your doorsteps within the hour."

Everyone jumped as Ami snapped her book shut. "Sorry," she said quickly. "I just realized something. I mean, I just understood. Ah, differentials, that is! I just understood _differentials_."

"Okay, Ami-chan," said Mako with a chuckle. "Congratulations, then."

"If you ever want help," Mamoru said, "not that I think you'll need it, but if you might, I liked Calculus quite a bit back in the day."

"'Back in the day'," Usagi echoed derisively. "How are you handling your arthritis, then, Mamoru-baka?"

"Usagi-chan." Minako clucked her tongue in disapproval. "Mamoru-san was making a nice offer to Ami. No need to be so protagonistic."

Rei slapped her palm to her forehead. "_An_tagonistic, Mina-chan!"

Minako shrugged a shoulder carelessly. "Something-tagonistic."

"See, odango?" Mamoru grinned at Usagi over Ami's head. "I _am _quite easy to get along with."

"Sure," said Usagi darkly, "because you're prejudiced. You're perfectly nice to Ami-chan the Genius, who's never failed a test and tried to throw it away and unfortunately met _you _in the process. You're prejudiced."

"Usagi-chan," Ami sighed. Even if the others couldn't, _she _detected the hurt in Usagi's voice. "Stop being so down on yourself. We formed our study group for a reason. Those grades will be up in no time."

Usagi's mouth twitched tentatively. "I hope so."

"Cheer up, odango," said Mamoru, standing and stretching his neck. "I'm sure underneath those dumplings there's a brain somewhere."

"You watch out, you baka," she growled. "You may just owe me your _life _someday, don't forget."

"I'm sure I already do, odango," he said quietly. "Ja ne, minna."

Ami watched him saunter towards the door, while Minako said, "Well, there! No problem at all!"

"Mamoru-san!" Ami cried, slapping her book on the table and scooting off the bench. "Wait!"

She heard a chorus of inquiries behind her, but she ignored her friends. Mamoru had paused, thank heavens, with one hand holding the door open.

"Mizuno?" he said expectantly.

"Can I talk to you outside?" she said, fidgeting with the small tube in her jeans.

Mamoru jerked his head, and she slipped out through the door he held open. "Arigato," she said quietly, and moved off to the side. She glanced around to make sure no passersby were too close. "Mamoru-san, my friends might not be altogether aware of how much the public knows about the Sailor Senshi, but I read every article I can find on them, every day." Her mouth twisted to one side as she glanced up at him guiltily. "You know too much," she murmured.

He frowned, another carefully placed expression masking the spark that Ami saw behind his eyes. "What do you mean, exactly?"

"'Freeze'?" she quipped. "'Throwing your tiara'?"

"Tiara? I never said anything about Sailor - about a tiara."

Ami fought to repress a smirk; he'd almost slipped up. "Alright, Mamoru-san. I'll go along with that. It's true: the general consensus is that Sailor Mars attacks with fire, Jupiter with lightning, Venus with - with love…? Well, you know what I mean, and Mercury with - water-related things. That's mostly because of our names, and our outfits, wouldn't you agree?" She didn't wait for a response. "Well, the articles I've read say that, at any rate. But very few people know that Mercury has a freezing attack, or that she's the… calculator." Ami blushed. "Not the electronic calculator, I mean, but…"

"What are you insinuating, Mizuno?" said Mamoru bluntly.

"I'm not done," Ami said, almost interrupting him. She surprised herself with her own briskness. "You called our enemies 'The Dark Kingdom'. The only name I've ever heard in reference to who we fight is 'youma'. People call them _youma_, Mamoru-san. I don't know where you got the Dark Kingdom bit from, if you're not…"

"I heard you talking yesterday!" Mamoru insisted indignantly. "Before you realized I was there, I heard you say _Dark Kingdom!"_

Ami racked her memory, trying to recall if the phrase had indeed been uttered in that short time before the girls had screeched to high heaven that Mamoru was there. It was hopeless; the frenzy that had followed dominated her recollections. "Then you're very specific, Mamoru-_kun_. I'm sure that marvelous memory has gotten you through many a difficult university course."

He smirked at her shift in honorifics. "You know, Mizuno, you don't _look_ this vicious on the outside."

She grinned back, once more astonishing herself with how playful she felt, despite the impending severity of her accusations. "I let Rei-chan and Mako-chan take that role," she said, "appearance-wise." Ami took a deep breath. It was all or nothing from here. "That youma we fought yesterday scratched us up pretty bad, in some places. Got me under the arm." She rolled up her sleeve to expose the underside of her forearm. A long, tender, green-tinted line passed from her wrist to nearly her elbow. "It stung pretty bad, but my mother's a doctor, and I found some special ointment that worked better than normal antiseptic." She dug the tube out of her pocket and held it out to him. "Here. It'll be gone in no time."

Hesitantly, he took the tube. "You can't honestly think…"

"Maybe you're right," she shrugged. "Maybe I don't have enough proof. But the little things add up, Mamoru-san. You're his height, his build, his coloring - Sailor Moon has gone to great lengths to describe the _exact_ shade of his eyes." She grinned slightly. "But don't worry. I won't tell, either."

Again, the stony mask, void of reaction, slipped over his features. "Ever thought about being a prosecutor, Mizuno?" he asked, pocketing the ointment.

"Is that a confession?" she returned slyly.

"I've got nothing to confess." He smiled back tightly.

"Of course," she acknowledged. "Well, let me just say, in case it needs to be said, that you really ought to make up your mind about… about…" She paused and started over. "That_ Tuxedo Kamen_ really needs to decide how he feels about Sailor Moon, in the possibility that he now knows who she is but perhaps their alter egos get on a bit more agreeably than their real-life personas." She bit her lips and added, "All hypothetically, of course."

Mamoru shook his head with a sigh, though she could tell he was just as amused as she was. "Of course," he agreed. "Hypothetically. I'll see you around, Mizuno."

"You put up a good act, Mamoru-kun," she said softly to his back as he walked away. He just raised a hand in acknowledgement.

_Nothing to confess_, Ami contemplated as she pushed the door open once more. _Because he's really not Tuxedo Kamen, or because I've said everything for him?_

"Ami-chan!" said Minako impatiently when she returned to the booth. "What was that all about?"

"Why in the world would you run _after _that baka?" Usagi shook her head and took a swig of Makoto's water.

"Oh, it's nothing," said Ami, sliding next to Usagi. "I just wanted to make sure I was right about differentials."


End file.
